Breast Cancer Risk Drops When Diet Includes Walnuts

The risk of breast cancer dropped significantly in mice when their regular diet included a modest amount of walnut, Marshall University researchers report in the journal Nutrition and Cancer.

The study, led by Elaine Hardman, Ph.D., of Marshall’s Joan C. Edwards School of Medicine, compared the effects of a typical diet and a diet containing walnuts across the lifespan: through the mother from conception through weaning, and then through eating the food directly. The amount of walnut in the test diet equates to about 2 ounces a day for humans.

Hardman said that during the study period, the group whose diet included walnut at both stages developed breast cancer at less than half the rate of the group with the typical diet. In addition, the number of tumors and their sizes were significantly smaller.

“These reductions are particularly important when you consider that the mice were genetically programmed to develop cancer at a high rate,” Hardman said. “We were able to reduce the risk for cancer even in the presence of a preexisting genetic mutation.”

The paper notes that dietary modification studies do not show whether benefits result from what is added to a diet or what is removed. In this case, adding healthy fat and other components meant that unhealthy fat was reduced to keep total dietary fat balanced in the mice. Hardman said other studies have clearly shown, however, that multiple ingredients in walnuts reduce the risk of cancer or slow its growth.

Using genetic analysis, the Marshall study found that the walnut-containing diet changed the activity of multiple genes that are relevant to breast cancer in both mice and humans. Other testing showed that increases in omega 3 fatty acids did not fully account for the anti-cancer effect, and found that tumor growth decreased when dietary vitamin E increased.

Hardman said the findings highlight the vital role diet plays in health.

“Food is important medicine in our diet,” she said. “What we put into our bodies makes a big difference – it determines how the body functions, our reaction to illness and health. The simple stuff really works: eat right, get off the couch, and turn off the TV.

“The results of this study indicate that increased consumption of walnut could be part of a healthy diet and reduce risk for cancer in future generations,” she said.

The study was funded by grants from the American Institute for Cancer Research and the California Walnut Commission.

 

Reference

Hardmana WE, Iona G, Akinsete JA, Witte TR. Dietary Walnut Suppressed Mammary Gland Tumorigenesis in the C(3)1 TAg Mouse. Nutrition and Cancer 2011; 63 (6): 960-970.

 

 

Walnuts Are Top Nut for Heart-Healthy Antioxidants

A new scientific study positions walnuts in the No. 1 slot among a family of foods that lay claim to being among Mother Nature’s most nearly perfect packaged foods: Tree and ground nuts. In a report at the 241st National Meeting & Exposition of the American Chemical Society in Anaheim (27 March 2011), scientists presented an analysis showing that walnuts have a combination of more healthful antioxidants and higher quality antioxidants than any other nut.

“Walnuts rank above peanuts, almonds, pecans, pistachios and other nuts,” said Joe Vinson, Ph.D., who did the analysis. “A handful of walnuts contains almost twice as much antioxidants as an equivalent amount of any other commonly consumed nut. But unfortunately, people don’t eat a lot of them. This study suggests that consumers should eat more walnuts as part of a healthy diet.”

Vinson noted that nuts in general have an unusual combination of nutritional benefits — in addition those antioxidants — wrapped into a convenient and inexpensive package. Nuts, for instance, contain plenty of high-quality protein that can substitute for meat; vitamins and minerals; dietary fiber; and are dairy- and gluten-free. Years of research by scientists around the world link regular consumption of small amounts of nuts or peanut butter with decreased risk of heart disease, certain kinds of cancer, gallstones, Type 2 diabetes, and other health problems.

Despite all the previous research, scientists until now had not compared both the amount and quality of antioxidants found in different nuts, Vinson said. He filled that knowledge gap by analyzing antioxidants in nine different types of nuts: walnuts, almonds, peanuts, pistachios, hazelnuts, Brazil nuts, cashews, macadamias, and pecans. Walnuts had the highest levels of antioxidants.

Vinson also found that the quality, or potency, of antioxidants present in walnuts was highest among the nuts. Antioxidants in walnuts were 2-15 times as potent as vitamin E, renowned for its powerful antioxidant effects that protect the body against damaging natural chemicals involved in causing disease.

“There’s another advantage in choosing walnuts as a source of antioxidants,” said Vinson, who is with the University of Scranton in Pennsylvania. “The heat from roasting nuts generally reduces the quality of the antioxidants. People usually eat walnuts raw or unroasted, and get the full effectiveness of those antioxidants.”

If nuts are so healthful and nutritious, why don’t people eat more? Vinson’s research shows, for instance, that nuts account for barely 8 percent of the daily antioxidants in the average person’s diet. Many people, he said, may not be aware that nuts are such a healthful food. Others may be concerned about gaining weight from a food so high in fat and calories. But he points out that nuts contain healthful polyunsaturated and monosaturated fats rather than artery-clogging saturated fat. As for the calories, eating nuts does not appear to cause weight gain and even makes people feel full and less likely to overeat. In a 2009 U. S. study, nut consumption was associated with a significantly lower risk of weight gain and obesity. Still, consumers should keep the portion size small. Vinson said it takes only about 7 walnuts a day, for instance, to get the potential health benefits uncovered in previous studies.

Nutrition Information about the health benefits of walnuts with dietitian Cara Rosenbloom.

 

In-Shell Pistachios: The Original ‘Slow Food?’

New research: In-shell pistachio consumption decreases calorie intake:

LOS ANGELES, July 14, 2011 – Two studies published in the current on-line issue of the journal Appetite indicate that consuming in-shell pistachios is a weight-wise approach to healthy snacking, offering unique mindful eating benefits to help curb consumption and decrease calorie intake.

The first study found that participants who consumed in-shell pistachios ate 41-percent fewer calories compared to those who consumed shelled pistachios. The second study revealed that pistachio nut shells can provide important “visual cues” as a reminder of consumption that translate into reduced calorie consumption. Both studies further underscore that in-shell pistachios, which are one of the lowest calorie nuts, are a practical, everyday snack for weight management.

“In-shell pistachios are the original ‘slow food.’ The findings of these studies demonstrate that pistachios, as one of the only in-shell snack nuts, help slow consumption; and further, that the empty shells offer a visual cue, reducing calorie intake,” said behavioral eating expert and study author, James Painter, Ph.D., R.D., Chair of the School of Family and Consumer Sciences at Eastern Illinois University. “In fact, the term ‘Pistachio Principle’ has been coined to describe a simple technique that can be used to help fool yourself full.”

In-Shell Pistachio Consumption Curbs Calories by 41-Percent Compared to Shelled Pistachios

The first study published in Appetite involved 140 university students assigned to consume either in-shell pistachios or shelled pistachios during class time. Both groups of students were provided a 16-ounce cup and asked to self-select a portion of pistachios to consume during class. Each student’s cup of pistachios was weighed before consumption began. As students left the classroom, the remaining pistachios were weighed and recorded; total weight and calories from the consumed pistachios was also calculated. Those who chose shelled pistachios consumed an average of 211 calories while those who chose in-shell pistachios consumed an average of 125 calories, a 41-percent decrease in calorie intake.

The second study published examined the potential role of pistachio shells as visual cues of intake. Study subjects included 118 faculty and staff from a Midwestern university, all of whom were provided a pre-weighed 16-ounce bowl filled with four ounces of in-shell pistachios to keep on their desk over the course of two workdays separated by a day of no pistachio consumption. Participants were told they could consume pistachios at their leisure during the day and were also provided a second 16-ounce bowl to discard the pistachio empty shells.

The subjects were randomized using a crossover design to one of two groups. For the first group, the bowls with pistachio shells were not emptied until the end of the day. For the second group, the bowls with pistachio shells were emptied every two hours. Pistachios were added in two-ounce increments if the amount in the bowl had been reduced to approximately half or less of the starting amount.

“When leftover pistachio shells remained on the desk throughout the day, calorie consumption of pistachios decreased by 22-percent compared to when nut shells were routinely removed,” said Painter. “Choosing in-shell pistachios instead of shelled nuts is a simple way to decrease calorie consumption without restriction. This is in keeping with existing research showing that when a person has visual cues of ‘leftovers,’ such as pistachio shells, they can see how many or how much they have eaten, helping to control portion size and consumption.”

Pistachios – “The Skinny Nut” – Support Weight Management

This new data reinforcing the mindful eating benefits of in-shell pistachios adds to the existing body of research supporting pistachio’s weight management benefits. According to researchers at the University of California Los Angeles, choosing to snack on pistachios rather than pretzels supports body mass index (BMI) goals. And research conducted by the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA) and recently published in the British Journal of Nutrition found that fat in pistachios may not be completely absorbed by the body, indicating that pistachios may actually contain fewer calories per serving than originally thought.

In addition to the data on pistachios, a recent study by researchers at Harvard University found that consumption of nuts, as well as vegetables, whole grains, fruits and yogurt, was inversely associated with weight gain with nuts exhibiting a (-).57 pound effect on body weight.

Pistachios are one of the lowest calorie nuts with 160 calories per 30 gram serving (approximately 1 ounce). They also offer the most nuts per serving, providing about 49 kernels per 30 gram serving (approximately 1 ounce), when compared to other popular snack nuts – comparatively, almonds have 23 in a serving, walnuts 14 halves and cashews, 18. Pistachios are also a good source of fiber and protein.

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References

Li Z, Song R, Nguyen C, Zerlin A, Karp H, Naowamondhol K, et al . Pistachio nuts reduce triglycerides and body weight by comparison to refined carbohydrate snack in obese subjects on a 12-week weight loss program. J Am Coll Nutr 2010;29 (3): 198-203.

Baer DJ, Gebaur SK, Novotny JA. Measured Energy Value of Pistachios in the Human Diet. Br J Nutr. 2011 Jun 28:1-6. [Epub ahead of print].

Mozaffarian D, Hao T, Rimm EB, Willett WC, Hu FB.Changes in diet and lifestyle and long-term weight gain in women and men. N Engl J Med 2011; 364 (25): 2392-404.

 

A ‘Nutty’ Solution To Type 2 Diabetes Management

Eating nuts daily could help control type 2 diabetes and prevent complications.

TORONTO, Ont., July 12, 2001–Eating nuts every day could help control Type 2 diabetes and prevent its complications, according to new research from St. Michael’s Hospital and the University of Toronto.

In the research, published online by the journal Diabetes Care, a team of researchers led by Dr. David Jenkins (University of Toronto Department of Nutritional Sciences; St. Michael’s Hospital Risk Factor Modification Centre) reports that consuming two ounces of nuts daily as a replacement for carbohydrates proved effective at glycemic and serum lipid control for people with Type 2 diabetes. The article, entitled “Nuts as a Replacement for Carbohydrates in the Diabetic Diet,” is available here:http://care.diabetesjournals.org/content/early/2011/06/02/dc11-0338.abstract

“Mixed, unsalted, raw, or dry-roasted nuts have benefits for both blood glucose control and blood lipids and may be used as part of a strategy to improve diabetes control without weight gain,” said Dr. Jenkins, who also has appointments with St. Michael’s Division of Endocrinology and Metabolism and the U of T’s Department of Medicine. He also serves as Canada Research Chair in Nutrition and Metabolism.

Jenkins and his colleagues provided three different diet supplements to subjects with Type 2 diabetes. One group was given muffins, one was provided with a mixture of nuts including raw almonds, pistachios, walnuts, pecans, hazelnuts, peanuts, cashews, and macadamias, and one group was given a mixture of muffins and nuts.

Subjects receiving the nut-only supplement reported the greatest improvement in blood glucose control using the glycosylated hemoglobin (HbA1c) test. The nut diet subjects also experienced a reduction in low-density lipoprotein cholesterol (known as LDL, or “bad cholesterol”). The subjects provided the muffin supplement or mixed muffin-and-nut supplement experienced no significant improvement in gylcemic control but those receiving the muffin-nut mixture also significantly lowered their serum LDL levels.

“Those receiving the full dose of nuts reduced their HbA1c [the long-term marker of glycemic control] by two-thirds of what the U.S. Food and Drug Administration recognizes as being clinically meaningful for therapeutic agents. Furthermore, neither in the current study nor in previous reports has nut consumption been associated with weight gain. If anything, nuts appear to be well suited as part of weight-reducing diets,” Dr. Jenkins said.

“The study indicates that nuts can provide a specific food option for people with Type 2 diabetes wishing to reduce their carbohydrate intake.”